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We herein report on iminium salts derived from Ishikawa's reagent Et2N‐CF2‐CHF‐CF3. The reaction with P(C2F5)3F2 afforded [Et2N=CF‐CHF‐CF3][P(C2F5)3F3] as an ionic liquid. The fluorine atom in the cation in α position to the nitrogen atom is labile towards nucleophilic substitution as demonstrated by the reaction with SnCl2 where an exchange of the fluorine by a chlorine atom took place. Upon contact with water the fluorine atom is substituted by a hydroxyl group. The reaction of Ishikawa's reagent with P(C2F5)2F afforded the zwitterionic [P(C2F5)2F3{C(NEt2)(CHF‐CF3)}]. Most likely [Et2N=CF‐CHF‐CF3][P(C2F5)2F2] was formed transiently. The anion is obviously sufficiently nucleophilic to attack the susceptible α‐fluorine atom of the cation. During several months Ishikawa's reagent loses hydrogen fluoride, which reacts with glass producing SiF4 which abstracts a fluoride ion from Ishikawa's reagent affording [Et2N=CF‐CHF‐CF3][SiF5].